Security News > 2023 > June > Microsoft shares workaround for Outlook freezes, slow starts
Microsoft is working to address a known issue affecting Outlook for Microsoft 365 customers, causing slow starts and freezes as if Offline Outlook Data Files are being synced right after launch.
Users will see errors saying, "Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. The attempt to log on to Microsoft Exchange has failed."
The Outlook freezes and very slow starts happen during cache re-priming, which occurs when creating new profiles or turning off shared calendar improvements.
This happens because non-Office MAPI apps like MFCMAPI and Outlook will arrive at different conclusions, causing unexpected hangs and slow starts.
In April, Microsoft fixed another issue blocking Outlook for Microsoft 365 customers from accessing their emails and calendars.
Microsoft fixes Outlook issue blocking access to emails, calendars.